| 研究課題/領域番号 |
19K04529
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| 研究機関 | 静岡大学 |
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研究代表者 |
Moraru Daniel 静岡大学, 電子工学研究所, 准教授 (60549715)
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| 研究期間 (年度) |
2019-04-01 – 2022-03-31
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| キーワード | Esaki diode / semimetal / donor-acceptor pair / band-to-band tunneling / silicon-on-insulator |
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| 研究実績の概要 |
This research aims to demonstrate that highly-doped silicon can exhibit properties of "semimetal". For that, we studied highly-doped silicon-on-insulator (SOI) tunnel (Esaki) diodes with depletion layer co-doped with phosphorus (P) donors and boron (B) acceptors at high concentrations. We reported, for the first time, single-charge band-to-band tunneling (SC-BTBT) at low temperatures. This has been supported by simulations suggesting that quantum dots are formed by clusters of non-compensated donors in the nanoscale depletion-layer.
We also reported the role of donor clusters for single-electron tunneling (SET) in selectively-doped SOI transistors. It was shown that the tunnel resistance modulation is critical, providing insights for high-temperature SET operation via dopant quantum dots.
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| 現在までの達成度 (区分) |
現在までの達成度 (区分)
1: 当初の計画以上に進展している
理由
This research was organized in several parts.
First, new Esaki diodes have been fabricated in SOI substrates, with high concentrations. New designs of pn/pin diodes with gates have been implemented using thermal-diffusion doping. However, a rapid thermal processing (RTP) system has been purchased and installed this year and will be used for abrupt pn junctions.
Second, IV characterization of tunnel diodes and highly-doped transistors has been carried out. This revealed band-to-band tunneling via dopant-induced quantum dots in the nano-devices (Appl. Phys. Lett. 2019). This is a key milestone for demonstration of "semimetal" behavior of highly doped (co-doped) nanoscale Si.
Third, the properties of donor-acceptor pairs in nano-channels have been analyzed by first-principles simulations.
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| 今後の研究の推進方策 |
The next research will also be carried out in several parts.
First, IV characteristics will be measured for highly-doped pn Esaki diodes with gates. By controlling gate voltage, we expect to control single-charge band-to-band tunneling via dopant states. This mechanism can probe the properties of "semimetal" of highly-doped nanoscale-Si.
Second, rapid thermal processing (RTP) will be tested for design of abrupt pn junctions. This will allow the development of new fabrication for high-concentration abruptly-doped Esaki diodes.
Third, first-principles simulations will be used to study the interplay of donors and acceptors in co-doped nanoscale Si. The simulation results will be correlated with experimental measurements not only for Esaki diodes, but also for co-doped nanoscale Si transistors.
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